


Unexpected

by rosecolouredspectrespecs



Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Cunnilingus, Eating out, F!Byleth, F/M, Fe, Fire Emblem - Freeform, NSFW, Pegging, Setleth, Smut, also happy 30th anniversary to fire emblem, commission for a friend, fe3h - Freeform, fire emblem: three houses - Freeform, flustered seteth, seteth x byleth, sinning in seteth's office, this was only supposed to be 2k words oops, vaginal intercourse
Language: English
Status: Completed
Published: 2020-04-21
Updated: 2020-04-21
Packaged: 2021-03-01 18:28:54
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,198
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23761591
Author URL: https://archiveofourown.org/users/rosecolouredspectrespecs/pseuds/rosecolouredspectrespecs
Summary: She could hear the abrupt sharp inhale that he took from the other side of the confessional. Byleth could just picture that handsome blush masking his entire face, that spark of red amidst the striking green of his eyes. She relished in her imagination for a moment before he spoke, breaking the silence.“G-go and pray. For in p-prayer you will be forgiven. The Goddess g-gives amnesty to all sinners who repent.” The shake in his voice was everything she could have asked for. She had to stifle a triumphant giggled. She had him right where she wanted him.-Byleth likes to count the ways she can fluster Seteth until he finally gets the picture.
Relationships: My Unit | Byleth/Seteth
Comments: 3
Kudos: 90





	Unexpected

**Author's Note:**

  * For [foxyjiji](https://archiveofourown.org/users/foxyjiji/gifts).



“This was unexpected, Professor,” Seteth said, taking a seat across from Byleth. She greeted him with a smile, a real smile, one that the world didn’t get to see very often. She took the teapot from its resting place and poured into his cup. He nodded, offering his thanks, before holding the delicate china to his lips. “Oh.” He stopped. Byleth tilted her head, stopping herself mid sip of her own cup.

“Oh, it is nothing. This is my favorite tea. It has been a while since the last time I have had it brewed, let alone brewed for me. I am just pleasantly surprised, that is all. You have my sincerest thanks,” his smile was warm and genuine. The corners of Byleth’s lips pulled into a soft smile again as she watched him take his first real sip. Though his eyes were closed, she could tell from the creases in the corners that he was content. She felt a small sense of accomplishments in that he had noticed her choice in tea, that her quiet ways of studying those around her could pay off in these small little instances. 

Byleth took a sip of her own cup, the liquid still hot against her lips but soothing all the same. It was quiet aside from the chirping of birds and the breeze rushing through the bushes around them. Normally the gazebo was a serene spot, perfect for teatime or curling up with a good book. Or grading papers. The quiet stillness was calming, after all Byleth preferred to be on the listening side of a conversation. It was a few moments before Seteth spoke up. 

“I do hope you will inform me of any issues you may encounter in the monastery. I know I speak harshly at times, but I hope you understand that I am merely doing my job. I put up a stiff front with people, due to my position. But that’s not really me. If there’s anything I can do for you, please tell me,” he said, a soft smile spread across his lips.

“Of course, I understand. Not really you? How does someone learn what you’re really like if all you do is work and no play?” Byleth spoke with a hint of playfulness in her voice.

“I do not always work, although that does occupy the majority of my time. Though when my own thoughts grow tiresome, I go fishing. It relaxes me. There’s just something nice about sitting in the quiet, surrounded by nature.” He paused, gauging Byleth’s reaction. Her lashes blinked, eyes full focused on him. “You should join me sometime.”

Byleth smiled in return, a genuine smile, which let him know that she would some day. She, too, enjoyed a spot of fishing. Maybe it was the silence that she liked, or the few passing moments where she didn’t need to be in control. Either way, she’d love to join him. All the better to get closer to him anyway. She reached for a pastry at the same time as him. Their hands bumped, and Seteth was the first to draw back, frantically expressing his apology and insisting that she take that one and that he didn’t really want it. The blush that dressed across the bridge of his nose and cheeks was cute. Byleth made a mental note of that.

-

Byleth approached the fishkeeper with a smile like she always did. It was a perfect day for some fishing. She knew that the dining hall was running a little low on supplies. She had already visited her garden in the greenhouse and harvested what edible plants she could for the day, and she had perused the sellers carts in the marketplace for some things and spent a pretty penny, it might do her well to collect some supplies that didn’t require any gold to perform. The fishkeeper advised her that someone was already using the dock and that it might be best to wait till later when she could take full advantage of the pond. Someone was already here? She was the only one who came here during her free time at this hour of the day. She went to investigate.

The end of the dock certainly was preoccupied. She could recognize those green locks and lapis robes anywhere. She approached him, boots echoing from the wood of the dock.

“Ah, Professor. Care to join me?” He didn’t turn around to greet her. How could he have known it was her? He patted the space next to him for her to sit down. She did.

“I am glad you decided to come. The glow of the pond usually means that there are some exceptionally rare species of fish today. Those are my favorite times to come out here. If I end up catching one of those less-common fish, I love to bring it back for Flayn. Seeing the joy on her face is absolutely priceless. It is the little things, I suppose,” he sighed, finally turning to Byleth. Her eyes were focused on the fishing float in the water. It looked strikingly familiar.

“Ah, yes. The float. I do believe it was you that gave me this one for my birthday,” he almost tripped over his words. And there it was again. That same blush pinched at the apples of his cheeks. Byleth liked that. “I do have to admit that this one is my favorite. You have my continuous gratitude.”

She nodded. The air was silent again aside from the splashes from the pond and the occasional echo of church bells from the monastery behind. Then the float disappeared. Both of them gasped and laughed as he reeled in the line. A Teutates loach.

“I hate to be picky, but this is not the one I came here for. You got off easy this time, my friend.” He took the hook from its mouth and held it tight to show Byleth before releasing it back into the pond. “You know, you could try casting a line yourself. You might be quite good at it.”

“Are you saying that I could be skilled at handling a rod?” She smirked. She could already see that same blush creeping up his cheeks. 

“I uhm, well, yes. A fishing rod. It is q-quite easy once you learn how, which I am sure you already know anyway. Perhaps, you should just try it,” Seteth tried to keep his voice from shaking. Byleth reached over to take the fishing rod, hand brushing against his thigh on her reach. She could feel his body go tense and felt a small sense of accomplishment in that. She cast the line and almost immediately the float went under and reeled in the line. Sure enough, a Fodlandy. The look on Seteth’s face was priceless.

“You should take this back for Flayn. I’m sure she will really appreciate it,” Byleth said with a wink.

-

Byleth wasn’t sure if her affections were being taken the way she wanted them to. Perhaps she needed to be a bit more bold with her actions? Her words? Her words were few but she knew they had meaning. After all, if she was really trying to win the affection, and get into the good graces of, the archbishop’s second-in-command she would have to prove to be sneakier than she once thought.

Sunday evenings were always reserved in the cathedral for prayer time and confession. While the organ swelled through its open halls, the whispers of prayers were drowned away. Byleth eyed the confessional. There was one way to find out. She pulled aside the halfway closed curtain and took a seat.

“Forgive me. I’m not sure how long it’s been since my last confession, if I have been at all,” she started. She wasn’t sure how to do this type of thing. She wasn’t particularly religious, even considering the fact that the blood of the Goddess herself flowed through her veins.

“The Goddess does not judge. Please, bear your sins before Her.”

The exact voice she was hoping for. And she knew that he had to have recognized her own voice as well. If he could identify her by the echoes of her boots then he surely could pinpoint her by the timbre of her own voice. She smirked to herself. Time to be bold.

“I do have to confess, my mind and my heart have not been pure as of late. I have been having…thoughts about one of the members of the church, someone of important standing. He’s a strong leader, a great teacher, and fierce in battle. And yet, I cannot stop the thoughts of taking him to bed.”

She could hear the abrupt sharp inhale that he took from the other side of the confessional. Byleth could just picture that handsome blush masking his entire face, that spark of red amidst the striking green of his eyes. She relished in her imagination for a moment before he spoke, breaking the silence.

“G-go and pray. For in p-prayer you will be forgiven. The Goddess g-gives amnesty to all sinners who repent.” The shake in his voice was everything she could have asked for. She had to stifle a triumphant giggled. She had him right where she wanted him.

-

The swing of his office door startled him. He was hard at work scribbling all sorts of notes upon the parchment of his desk. Whether it was personal work on a fable or a report for Lady Rhea, it was not important. Byleth filled the space in the doorway, silhouette perfectly outlined in the shadows of the flickering candles. She closed the door behind her, tossed a satchel into the corner of the room and approached his desk. Knocking his work aside, she pushed herself up onto his desk, not allowing him to be distracted on anything else. Only her.

“P-professor! You really should not be sitting up here. I am trying to get some work done,” Seteth stammered, trying to avert his gaze from Byleth, cheeks a distinguished shade of red. She gripped the front of his tunic.

“Please, Seteth. I don’t think I can be any more clear. I want you…please,” her face was dangerously close to his, and he could feel her hot breath on his cheeks. The moment he took to collect his thoughts felt like a lifetime, and he had experienced many of those. His thoughts raced a mile a minute. Everything was adding up. The way she looked at him during tea. The subtle brushes up against him. The way her words meant so much more than what she said…and what she said during confession. He never kept it a secret to himself that he wanted her in that same way. But as a man of the church, someone in his position of power, his piety, would it be appropriate? Or was this the way the Goddess was rewarding him? The thought was silly, but here she was, the embodiment of Her before him beautiful and radiant. With eyes that were full of such mystery, with strength unimaginable, with wit beyond measure, and a body that he was so sure would fit perfectly with his. 

“Did you lock my office door?” He hesitated.

“Of course. I am no fool.”

He held fast to her face and kissed her hard on the mouth. Byleth was taken by surprise at how forceful he was, but she was in no position to complain. Her own fingers released the grip they had on his shirt and tangled through his emerald locks. He kissed her harder, tongue forcing its way past her lips and exploring her mouth. She tugged on the strands and a soft moan escaped his lips. She smirked into the kiss. She softly pulled away and trailed her kisses from the corners of his mouth down to his neck, hands moving as well. She started to unbutton each button as quick as she could, kisses trailing swiftly behind.

“How many of these damn things are there?” she growled in frustration. This earned her a laugh.

“Imagine how difficult it is to prepare each morning if you find this challenging.”

“Maybe I won’t have to imagine…”

Seteth assisted her in helping him undress. Though helpful as his intentions may have been, he kept letting his mind wander to the reality of the situation and became continually flustered. Byleth pressed another kiss to his lips while shrugging his coat from his shoulders. There was hesitation in his kiss. She pulled away, blinking her big doe eyes at him and waited for a response.

“Forgive me, I-I am…uhm, well, it has just been a very long time since I have done anything of this sort. It has been more years than I care to remember, and to say that this situation makes me feel young might not be the right thing to say, but please, forgive my naivety,” his eyes did not meet hers.

“Seteth, there’s nothing to worry about. Just relax,” she kissed him again, working to free him of his tunic underneath. 

She felt his body relax against hers, his hands now working to free her of her own complicated ensemble. Her palms explored over his exposed chest, feeling over his defined muscles. She pondered for a moment why he kept his perfect physique hidden under the baggy, flowy robes he wore on the daily, forgetting a moment that he was a man of the church. They were in a church, in his office, half dressed and keeping voices hushed. She preferred not to think about it like that. Her thoughts were drawn away by his mouth on her neck, pace getting hungrier and more desperate the more clothing he rid her of. He wrapped an arm around her waist and pulled her off his desk and into his lap, mouth focusing only on her now exposed breasts with fervor. She moaned, louder than she intended, and her own face prickled with a blush. He stopped his ministrations for a moment to look up at her, then the door, and back to her. He chuckled, brushing her cheek with his palm. His thumb rested on her lower lip, which she took into her mouth and sucked.

He wasn’t ready for that, and his own groan against the soft flesh of her chest rumbled into her skin. He removed his thumb and traded it for another pair of fingers, his free hand slowly working her shorts free from her hips. She gripped his wrist to stop him, leaning into his own chest for support as she assisted him by kicking off her boots. It was going to be harder than she thought. Carefully climbing off his lap, she rolled her own shorts down her legs. His piercing green eyes now blown with lust and focused on every inch that the fabric moved. Her tights followed soon after. She made it a bit of a show, rolling them down her thighs, down each calf and kicking them off her toes. Seteth lazily palmed between his own legs. 

She let him take a moment to take in the sight of her naked body before hoisting herself back up onto his desk. She took his wrist, the hand resting on his thigh, bringing back his fingers to her mouth. He stood, arm wrapping behind her again for support. He pulled his fingers from her mouth and replace them with a kiss. His slick fingers brushed up against her own slick folds. He shivered, a hesitation in his kiss, before he pushed one inside. Byleth bit down on Seteth’s bottom lip, causing him to groan into their kiss once more. His free hand finagled with his trousers, to no help of Byleth who’s hands were propping her up and one concealing her face. For a man who hadn’t been intimate in millennia, he certainly hadn’t lost his touch with his very talented fingers. It was almost immediately that he found Byleth’s g-spot. Brushing up against it, stroking in patterns, riling her up and calming her over and over. She was so wet against his hand, juices dripping down her inner thighs. He gave up trying to remove his trousers, letting them settle around his ankles. Through her fingers, he could see Byleth’s beautifully flushed face with her eyebrows knit and her lips parted. Her full chest rose and fell with each heavy breath. He lowered his head to take her with his mouth, tongue darting out pleasuring her alongside his eager fingers. This time the professor couldn’t hold back her cry. Seteth didn’t care who heard anymore. He took her clit between his lips and stroked that sweet spot, knowing full well it would push her over the edge. 

And it did. Her hands rushed to his head, gripping onto his hair full force as her body shook. He stayed focused on his actions, afraid to falter, wanting her to feel so good through it all. He couldn’t help but feel a bit smug that this was all his doing. 

Before she could catch her breath, he kicked off his own boots and trousers and positioned himself at her opening. He teased her with the tip of his cock, afraid to press inside. He looked up at her again. Her eyes blown wide, her skin glistening with a thin film of sweat. She was gorgeous, so beautiful and laid bare for him like this. She gave him her nod of approval and reached down to guide him inside. He pushed flush with her body and held there frozen with desire. He had almost forgotten how good it felt to be connected with someone like this. Two bodies becoming one. The last time he remembered being so moved during intercourse was when he would make love to his late wife. Had it really been that long already? How long had it truly been since he had allowed himself to succumb to his desires? He considered himself lucky, blessed even, to be where he was now. Here, with Byleth. He felt his chest tighten and he swallowed hard. He didn’t want to acknowledge how misty-eyed he’d just become over these thoughts. Not right now when Byleth was so tight around him and she felt so good. He couldn’t let himself get too emotional right now. He moved, slowly at first, picking up his pace. The quicker he moved, the more she made that cute face behind her fingers that he knew he loved already. Her soft mewls of pleasure mixed with his own grunts melded like music.

And then he found himself close to climax already. Already. The harsh reality of how long it truly had been. Maybe he could have lasted longer if he had been more experienced or if her body hadn’t been milking him like it was made for him. Byleth moved her hand from her face, the pink blush across her cheeks was darling and he was suddenly sure that’s why she reveled in his own blush. Her lips parted to speak.

“Seteth…please.”

He came with a hearty moan. One that was sure to have been heard in the offices next door and could only hope that Professor Manuela and Professor Hanneman were away from their offices. He could worry about that later. She clenched around him, milking every drop from him, her own moans blending with his own. He held onto her, arms wrapping completely around her body and held her to his strong chest. His head was spinning. Nothing he could have accomplished on his own could amount to how good this felt both to his body and his spirit. 

This was nice. Holding someone like this, being with someone like this. His heart swelled around this moment. He’d never let himself forget it. He nuzzled into her, his beard scratching along her forehead. She chuckled before lightly pushing him away.

“Don’t think that I’m done with you yet,” she eased herself off his desk, uncaring of the mess driping down her legs. She looked around her. Paperwork, quills, closed bottles of ink, well, most of them closed, scattered over the floor. She was careful to watch her step as she found her satchel. Inside she pulled out a harness and what looked like…

“I figured it had probably been a long time since someone had their way with you, if at all. Care to try this out?” A strap on. It wasn’t that the thought had never crossed his mind, he just had never experience anything like that before. She dipped back into her bag, brandishing a bottle of oil.

“You will not let a man catch his breath first?” he chuckled, breath still in soft pants.

“Not in battle, not in the bedroom. Besides, I knew you wouldn’t have agreed to start with this,” she winked. She hooked the toy to her harness and wore it proudly. Seteth let out a small chuckle. “Come, Seteth. On the ground. All fours.”

Without hesitation, he obeyed. What did he have to lose? He was nervous and also a little excited. This has been one of the most productive days of his life in a very long time. The monotony was broken, and everything was certainly unexpected. All of this was unexpected. He regretted nothing. In fact, he was grateful. Part of him wished to send a prayer of thanks to the Goddess.

“I promise I won’t hurt you. Please let me know if you’re uncomfortable, okay?” Byleth knelt behind him, lubing up her fingers. She heard Seteth’s soft “mhm” from below. She used her knee to push his legs farther apart. She ran her finger around the rim of his opening, whispering sweet nothings to him urging him to relax before pushing inside. His soft sigh was enough to let her know that he was enjoying this. She slowly worked him open, adding a second finger.

“This…this is good. I expected it to be…much more?” Seteth said, voice soft and hesitant.

“Seteth, these are just my fingers. We aren’t there yet,” she giggled.

“Oh.” 

Her other hand palmed at his growing erection. Another sign that this was good. She heard that familiar hitch in his breath as she stroked his cock in rhythm with her fingers. Just when she was afraid he was going to hit the edge, she pulled away, both of her hands. His little disappointed whine was endearing. She lubed up the toy and positioned herself behind him.

“Just think…like wyvern riding,” she said, pressing the tip in.

“I assure you, Professor, that this is much more different than- OH!”

She laughed. She didn’t mean it in a rude way, she just wasn’t ready for that reaction. She allowed him to adjust around her before moving again. She kept her pace slow. Seteth moaned loud and wanton, so much more than he did in their prior engagement. His reaction was shocking yet satisfying. Who knew that Seteth had such a hidden submissive side to him? Byleth had a feeling this wouldn’t be the last time Seteth took the strap from her. The words spewing out of him were more vulgar than anything she had ever heard him say before. She hoped he wouldn’t remember anything he had said. 

Especially the begging. Seteth begged her to move faster, to move harder, his own hips moving back and forth in hopes to coerce her to do so. She complied, quickening her pace to match his own. He was holding himself up with one hand. She remarked how strong he was before noticing it was because he was using his other hand to pleasure himself. She wrapped her own hand around his, joining him in his erratic strokes. He was so close again already.

“P-professor…I-“

“Call me by my name.”

“Nn…Byleth!” He cried out, cum dripping down both of their knuckles as she continued to stroke him through his shaking orgasm. 

His body went limp, knees giving out as she pulled out of him. She rid herself of the harness and pulled him into her lap, stroking his hair soaked with sweat from his face and placing a kiss to the center of his circlet. The room was a mess. They were a mess. In the middle of his office. In the middle of the monastery. It was then that she was sure that they had been heard in the offices next door.

“Are you okay?” she said, taking his cheek into her palm and pressing a chase kiss to his lips.

“I…am more than okay. I am perfect. I am absolutely satisfied. I am…thank you. For all of this…” his voice went from excitable to soft. “I hope I was a suitable partner.”

She smiled. A true smile. One that reached the corners of her eyes. He knew that smile and he knew it well. “Of course you were. And I hope you will continue to be?” An eyebrow raised.

“I would be eternally grateful. Though next time, possibly this could occur in one of our quarters and not my office?” He laughed.

“I can make no promises.”

**Author's Note:**

> Comission for my lovely friend Kelsie!!


End file.
